<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript" charset="utf-8">
        /**
         * 递归
         * @param num
         * @returns {number}
         */
        function fact(num) {
            if(num<=1){
                return 1;
            }else{
//                return num*fact(num-1);
                return num*arguments.callee(num-1);
            }
        }
        var F = fact;
        fact=null;
        alert(F(5));
    </script>
</head>
<body>
</body>
</html>